Which of the following statements best explains why an increase in temperature of 5-10 Celsius degre — Kinetics Chemistry Question

STEPS:

1. Understand Temperature and Molecular Kinetic Energy: According to the Kinetic Molecular Theory, the temperature of a substance is a measure of the average kinetic energy of its particles. When temperature increases, particles move faster on average.
2. Apply Collision Theory: For a chemical reaction to occur, reactant particles must collide with one another. However, not every collision results in a reaction. To be "effective," a collision must meet two criteria: the particles must collide with sufficient energy (equal to or greater than the activation energy, $E_a$) and with the correct orientation.
3. Analyze the Effect of Temperature on Collisions: An increase in temperature has two effects on collisions:
* Frequency: Particles move faster and collide more often.
* Energy: A much higher fraction of the particles now possess kinetic energy that exceeds the activation energy barrier.
4. Identify the "Substantial" Increase Factor: While the frequency of collisions increases slightly with temperature, the exponential increase in the number of molecules having enough energy to overcome the $E_a$ is the primary reason the reaction rate increases so substantially for a small ($5\text{--}10$ degree) temperature change.
5. Conclusion: Statement B is the best explanation because it encompasses the requirement for collisions to be "effective" (having enough energy) to drive the reaction forward.

WHY_OTHERS_WRONG:

• A) The activation energy for the reaction is lowered: This is incorrect. The activation energy ($E_a$) is a fixed energy barrier determined by the reaction mechanism. It can only be lowered by adding a catalyst, not by changing the temperature.
• C) The rate of the reverse reaction is increased: While this statement is often true (increasing temperature increases the rates of both the forward and reverse reactions), it is a consequence of the temperature change, not the underlying explanation for why the reaction rate increases in the first place.
• D) $\Delta H$ for the reaction is lowered: Enthalpy ($\Delta H$) is a thermodynamic property relating to the heat of the reaction, not the speed (kinetics). Changing the temperature does not significantly "lower" the $\Delta H$ in a way that explains reaction rates.
• E) $\Delta G$ for the reaction becomes more positive: A more positive Gibbs free energy ($\Delta G$) would indicate a reaction is becoming less thermodynamically favorable (less spontaneous). This would not explain an increase in the reaction rate.